This invention relates to the field of the automatic generation of animation and, more particularly, to an apparatus for generating video-representative signals which represent one or more operator-selected portions of a scene.
Animated films are in widespread use for educational and entertainment purposes. Animated films of reasonably high quality have traditionally been very expensive to make. The initial creative work includes generation of a basic story, a sound track, and basic character designs. Typically, a schedule is generated which describes the movements and timings of each scene to be produced, and layout sketches and "key" drawings are made which define the overall design of each scene. The so-called "key" drawings or frames are still frames which show extremes of action. In the traditional animation procedure, people known as "in-betweeners" are employed to sketch frames which fill in the action between key frames. After in-betweens are sketched by hand, the hand-drawn pictures are typically transferred onto celluloid-acetate sheets and are then painted in by hand to obtain the desired image coloration. All of these tasks render the production of animated films an extremely expensive proposition. An advantage of the traditional animation process, however, is that the animator has virtually complete artistic freedom and control over the resulting film; i.e. anything that is drawn can be made to move in a desired fashion and colors can be precisely selected.
A number of approaches have been proposed for employing electronic equipment to assist in the animation process. For example, some early approaches employed electronic graphical inputs, such as data tablet inputs, to allow an animator to freehand draw sketches which were electronically displayed on a cathode ray tube. The displayed figures can be photographed to obtain basic character outlines to work from in generating the animation as described above. More advanced techniques have employed relatively large scale computer systems to assist the animator and minimize labor. For example, one approach has been to design elaborate special purpose computer systems which can perform coordinate transformations that simulate motion of drawn figures. Techniques of this type are disclosed, for example, in the U.S. Pat. Nos. 3,364,382; 3,662,374; 3,689,917; 3,700,792; 3,710,011; 3,723,803 and 3,747,087. It has also been proposed that a relatively large scale digital computer could be employed to aid the animator; e.g., by automatically generating in-between frames by interpolation of lines appearing in successive key frames. A technique of this type is described, for example, in an article entitled "Towards a Computer Animating Production Tool" by N. Burtnyk and M. Wein which appeared in the proceedings of Eurocomp Conference, Brunel--United Kingdom, May 1974. Also of possible interest are the U.S. Pat. Nos. 3,637,997; 3,665,408; 3,835,245 and 3,944,997.
The described machine aided techniques, while potentially easing an animator's labors in various ways, do not adequately provide for the animator's needs in the domain of inputting image outlines into a computer for subsequent processing. In the formulation of animated films, there are numerous instances where the animator desires to utilize the outline of particular figures in existing images, where the existing images may be previously drawn sketches, photographs, or images on video tape. For example, a number of sketches of characters in an action sequence may have already been drawn, and an animator may desire to "input" the sketches to a computer-assisted animation equipment, such as the type described in the copending U.S. Application Ser. No. 752,114, filed of even date herewith. In such instance, the character to be stored is originally in the form of a "line drawing"; viz., the memory of the machine system is loaded with the points defining the outlines of the entered characters. This may be done, for example, by tracing the outline of the sketch onto a data tablet with a data pen. The tablet, in turn, transfers the coordinate points traversed by the data pen into the computer. However, the necessity of doing this for each sketch can take considerable time. Another instance where tracing onto a data tablet is a standard technique is where an existing image, such as a color photograph or a frame of an existing film, contains one or more characters which an animator desires to use in animation being generated. There is also a long-known technique in animation known as "rotoscoping" wherein natural looking animated characters are obtained by taking films of actual "live" characters in motion and tracing the outlines of live characters from the film. There is presently a need in the art to generate outline information in these and other situations, without the laborious task of tracking, cutting, or the like.
It is an object of the present invention to provide solutions to the prior art problems as set forth.